SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9ff5b29f6d4e8f97ed94024bb13a0e143df5e9fcc67a42be81c322e285ae442' 
  AND token = 'awkVZ090gNpZ0d4Iz8ZJeiKfXkgYOKCFGJjhZADw/WU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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