SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fdb4b1d493ac0988b3a85236b9dfefa29ad2144809048b8f2ae18660a5bc3b9' 
  AND token = 'ZSMAwyeiyxlC/WzI+yum/apQp8mwrAGImbEPdap9R0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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