SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18269cc7f86e4a9aa97ad7d052f14ce9b407978403ed322714870dac6917f7aa' 
  AND token = '91RcP6gcXgvwHXqhCksByzpp4lKsMx1Z5MMhwzeMnRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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