SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9bfacfc40ae115a4c8a3e18b291bdcb7fa139854e9170fc792498db2fc52863' 
  AND token = 'opHSxVhcEccABFV4Lz3kjoqvU4sM6/kbZQSOlen4wP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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