SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd76b7630302637841efef15988fde7e9106327931fcf1b47fec0be1e236131d8' 
  AND token = 'sDHgH+wf4dbAgwjIIXIhxI+Cbkg175g/KMNyvB8CVtw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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