SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f73e0cd22c17542e315582c1ef47791241d34cd307264dbd493cf4f6d690a1d3' 
  AND token = 'X9T5my4LzKoFEX2bqvGU2cOULZnpOcpCSqELnfmridY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00098

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}