SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1e5fb6caec9baece3205f8457e7f6016a3f685851cd0312cb92a9a88569c5f5' 
  AND token = 'v8RL0IN7qgZXfASN0t9xL9+YFoQM7HmkBGwFxBkcpl4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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