SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a457116b31d8626d85f4f2d37ef0fd27fadf3531d9bd992d65f72fd57091c0c' 
  AND token = 'QDn8v5HmxvmjS0ezh2BPDZv8ybbzm4vPQ+FlOyB5In0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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