SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '71f001f95fec733b385978e885068e84d07fa0b4584e9f02ba56a8de375a0ec3' 
  AND token = 'MLKZ3x2pDuHXsFRsxyc2PkNDw0Bl6yONqLMyTz61yG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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