SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'df07683817e0e3cf985215c6ef47b74c68db0c4de7283d9c9d481a6066603fd7' 
  AND token = 'nQjuG/w6HVhVYA9em+1pQWM3dUvnR1Hr7i8o5WXygLs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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