SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'afc2759ab91c7336558dc9ea26f29b4ca4bd754b3e75e401727fa1eceac9d31d' 
  AND token = '6VtAuP/KwRVnfvY+avqoxLxuY2jQru12EVCUQ/ZxlsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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