SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43d430e8b5b55305fc7fa78acfe1bbc572b871bc0b2aa9083a57b231921dfc31' 
  AND token = 'c8H+GiktKidowKG0h9nSkrGoJ7oLtLdJOsKjMiQstUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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