SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fb6afbb6fd42d33ca58f1e6b995968f4b09381bd4f994bf3a62a34b3bc0cf78' 
  AND token = 'zyDHT04jMv0z3P0fhYQqRAAVgMJu4FcYB4H6wGbgpuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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