SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d83c902523c6fac0b65235d0de44c06699fcb927de000fcc3eabde16fd6adfb' 
  AND token = 'aY6Gmt7sh7BGeAn8Vu7IQ46aq4t0pfGfutlDKeBTgBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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