SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be2ec67f3e6ac986e072ff859357f444dc416aece93b328f7b908bef4c0a7ce9' 
  AND token = '2b+UI31xwuaUnX7rKOcgiN0NdI2hj2DVDoDGqw9Kjz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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