SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '17ea938768b356f884d435d84021f8c1db14fef04605110237c00960221f6bb9' 
  AND token = 'h2p6OKrNiUqjdoUhYfnGIxQCGb8qahyanH+L3c71uJk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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