SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88f2cb7552e68bbe7d8dd781a3f65a272f4d6098c4d4f0e83e9a2b21289d72b7' 
  AND token = 'R8x3BHmgF8314yBdX3RU4hzg5xT3TzcsKXdM3bmGFwY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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