SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb7528b6503ec56bc4996d34719800d14f61db7a5a56936abbce9130f5a9536a' 
  AND token = 'v6wCpbFNItz0dpsvnqOGBLMnNLOPFpjvmocIYMgqmYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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