SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46acec90ee6e5fd0b1ec137fe3976d6f81f44fcdd438dac54ee0aa941446d0e5' 
  AND token = 'Rmnubr00i2CBNOJGSlO9Km/W3iDlLB0NrnnrdHz6Td4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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