SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c93f901abdd27fcaccba0c30808f32da318cc58eeb833d9548dc23a8bb50e929' 
  AND token = 'RTZ2pUulYIe2UuaUDJUhAj/oNdn9uKSfoiGX/VxmeCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}