SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cca8585a4816b17b32d88f3447a7672a3c7af28a395b717db6b355b2cb6df16' 
  AND token = '4vCcf9pmkfYc48B0UEH/sPZZ6DRl+I/5z7tTwrs3Hjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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