SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd4ae7a93463f3ea7eaaadf73bab36c8e3a2e1102e4567b399e95f79f3fb3346' 
  AND token = '/fBdZ+dwKPw6Oj26KQiLEyVGGSmgUrYzvjb4KIl/1mk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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