SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cf92819300f918910b9ac8aa7b40ff7c1627a2f5d268db2cded7c55a0a92a3e' 
  AND token = 'AU/cJ6L8Q988g4V0M1qxuCyg5ko1+jONcF3/ImeGAyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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