SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c61cea046c155301921c1d9961745ae6a187e11b8d699cf31c0088d9a039cd09' 
  AND token = 'yjasqeSjbfqmlvlF9JRbgHzuEORMD2adzDx0mHay5OA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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