SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ff7eadf04a0b61f24b5cfcaa16ec5376742aefd51b737d3b0ca052d26581b73' 
  AND token = 'XriR54sAedOkWiWP/gReARZ5MK0pE27Gs9hbvTODHjc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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