SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5ac87fb4a0f102f933b6381882d7ec1e80825c84b511339646339e4817ab371' 
  AND token = 'FE9kVlb0uHi+xOQt1RCi/2iy6JW0LdBquDc6v9J0KRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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