SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1391670e6bd43f43f51fc00a1721414bc7443b7aa41fcf712645e8e3e928ac04' 
  AND token = 'rEVtgC5s1jWqvQ9Gd3L1RYuEy+FPazwN8KO3MN43nII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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