SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f37215c866e08688c3fd114d70d14362783edd59d06532d571d18d5c8cef64f3' 
  AND token = 'PAn8SiBSYqEQ4Z1nIqawliK7X7HhJ10+wA5vqqLg+/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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