SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '402bffe48f1b12ae8d2cef6fba53b9e0c241b470894260409da95e941170362e' 
  AND token = 'Evnv4aUY92cse4E53Z2eqbrvdWjz7HOpVswbtcSIj4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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