SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55db8f0af380aab1618c4c4c22665bf12014d0fcec7aeee55592f3ef686f9c45' 
  AND token = 'POwiHCExyQYiJ2UG6JTL/Mr3OSvjbYjRzVCPBWHZDlY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}