SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79150443168efd1374cbf754e028dd67e9afc14d83d815ca37b92fc18dd2a788' 
  AND token = 'U4ZqyEAYVsCieefvosuypW9cgXsPyjgH6XRgFijRZ8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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