SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2651be4351ddd177b7a8aad6a7ea8fb4291f4c8de702c8421de9fdde908e9b87' 
  AND token = 'oHv91FPkWYGYrrL5bryxgl4Ife22Pgnd+vHhDqREUo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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