SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23050893c44a5c838fb4c269daeca56e26f0b492baa41a8094506debd6b4e3c8' 
  AND token = 'mW1gML/9QmIZEQxOCYTknbanxM/nzUZSXuBnp8NKIXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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