SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18b127491daeebc511c7b38bbb2190cb36c8f71aaa8a94ebe58922b4fad1f27c' 
  AND token = '4edmkkmaTZE75xpc4FxfoaBSmL2k2Yvh8eXWzVJvwoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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