SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd989de22eace0bc3ae06461090b31140096f65ca8ed286b764cf309883c38022' 
  AND token = 'hhoRQwxrJcD1WL617Lph6nH/dv7w+hH42xU1DukfkgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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