SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9dfe68c365adeab6c72b5749313fdb181f338a8fb1b5eca18e9317b15f2a798' 
  AND token = 'ax7UwgcY9JOedsbsUaxCe6vRguk7L37Y0Uxo73YbnhE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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