SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b3be1976d0da2a85858fc934f6f7772882076a1af62b1abaa412aa0f1246791' 
  AND token = 'BBWTV1CBypl+gYxu17jPqw8waaQyRnBojQTxlQFX+SI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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