SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a247d3c9ed6707b810a704b3a856c5a12e69a13ac819b2a37313dd128ed6a047' 
  AND token = '1O//UbD1Yx6YRTHhwxmxzt9mC+gGi+5KNvUp7TApRXE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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