SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7e61a792ef36be92033d0618df2fabe868bbcda0542124c521071ae807ac10d' 
  AND token = 'a2odEeWiZrFn47bF3pSh26iWUsgOH9ihKXiq+oAKdE4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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