SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84df7b2924eb1dc7be17c872522b4346b738dc2654a4191ffc1135831cea7e9b' 
  AND token = '9A0wasll9FB+wDRMOYgWUNRSLsgKObvAIGlIyY3/hYQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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