SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e21a7c91f7c94d34ba858a10bc4667a55af8e6980746c9042f1fa0871867d51b' 
  AND token = 'UnO94+ShFqIKTZYnQK7XN5XZTKPJR7NA/nvFPPGuLO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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