SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce0dfef08579152a3b76266bad950516931d2abf95c2cb4374d1f89dd393aeb9' 
  AND token = 'XxT7Eq6yZeZwDRyFJzFTXyWKlBXOEqieCnF7kHSy6SA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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