SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc44e9ff6ca9c253600c34399d3cc56365f71bf8443a92a75a057cfed50ebd59' 
  AND token = 'Ufj1Sq2dOh+UJD4ebEJnuRhvO5gtFXlioWHPKBuxFeQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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