SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5389199b3f392072ffcfd8f767085f5850a02971446682f08a6cdb43d83a49bd' 
  AND token = 'yXG6dvKgH/IUXPA7rOjErSnV+oDbAqACnLtVKtdwi9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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