SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4719916213af83a657b4b495f8c59f5434c390f9ec1646e8924d2d6ee76ff9ba' 
  AND token = 'vGsE5wUJVPwKhAL+ZIkkPlxfHzEOflJsP9bJEQj2LBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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