SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a19e056aa8077834cdcf4f7053dc0278031cf175818f7521e4c402e5a10d02d8' 
  AND token = 'ruNmaS2qo9I5tnUgBdvLF9J3oHGg7ilSX29jYvonAkg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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