SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4844a357afca4c5c372c0d1b99d6180c3619fb92bb468aa555fc5278b507874' 
  AND token = 'FbkSx1nD9xvdoFVrBnR4aY3vvTAK3Wgdqd448xKOeOU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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