SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe1a7be8b0588582ee06f69bfdecc55d5a965d44de1be02920ad091ad5a53af0' 
  AND token = 'wRdXbIwFl9spiJYGe8DSaIIV03xpWglwXlNh4xn87u0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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