SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09f3120a89a082039e2360e5b0c5c7528879474eaa235b72eacd1859b366a4eb' 
  AND token = 'uVsEoMG0zN9GuRkcBBONhQgr1fWqHWHio+inCYcl7gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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