SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f492a92befc97441f6cc67d6d6333da8d14a7510823c497514533a0a257852a9' 
  AND token = 'vnvavTlVh4rTwe/ojQmIZ1GpnCE6EndYGtly4t0yKzc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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