SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '552a0401cf5576b24dad28bf7d196510c5bb63e93259a79f60cb0beded7ede52' 
  AND token = 'vNugormU0w0TX9TiYxILLLaBG25QaRalnbOIfRml4jg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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