SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5503a65598cca5c8bc92761c9b301efbc4faf86339b3159c1d3309ab520247f1' 
  AND token = 'x3vz0/Wh8HMSZD7rnNiJDh8Zm3ZaF3oYg4QMkbA9OlA=' 
  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"
    }
  }
}