SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fdd1dd971f0e1d85979cf9374ee494b633c44c4a06de311b387af4e53a36504' 
  AND token = 'F5ClDWOOWXPCf1eznsUPuDzBZ7nbRSDr1QMc3gPmQmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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