SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '937e09d1ec9d84a7690bd240630d22fa8f44fac5bb83a0e432e04e3b760fdf0a' 
  AND token = '+YjBqMvkVEnPzHh/TiY82rsktWRWWlXdZwi9ZC6kuVI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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