SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d4cde5746c95ba0410a48887c74fa63f616a0c66e153c3ef8a59f106d0e0c32' 
  AND token = '6oOTDnkytxHNluOkTx6RMy2uEN5L2K5mqmaZI7O08Fc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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