SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9036f37dd2710c405c0963ed5fbf6a9bc18114cf114743522061c246409472c' 
  AND token = 'r0SE00ph95PtjIuBO//uqj6vOHV5ccM7dv9DupEMoZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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