SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef89a285642e59b92fd24c26a0b1cd2e6eea1772a77e35169127a9ba17e2ed4a' 
  AND token = 'KnHjxDMqKORJ/aswKUCAj/RdvgZe/jXbXLXluQ3Gj6I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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