SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed62906126375ec642161819d9da98dae702580c169b13df58927ac60153a131' 
  AND token = 'r9eYikXwfJwcZsPuzpyS5AfVOG1WI9W10DiHy9xUwrg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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