SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c94b0b2dc0ba23517b142e2f87c30e891c36355e6721eac7a3dab83347f22a3' 
  AND token = 'NNd/XDfqj3M4uQgBDwJnIwCvu0rjyRkPmqMGYbXLClg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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