SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '421311f63f2536fd041894d74d10be0be8bc00ebcfd18d53a6dc0cfa9cec4d8f' 
  AND token = 'EYmwON18F6xIvOSctaVbIHH9XLb3vDU0f8JEM/tuiK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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