SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73b53088d159fdebdc71fb1bd8df8f264d63696f2e3eba8402537ef608e07496' 
  AND token = 'APJgSYs9PsGJv/XVb+HFf0fiB4XpBOe9eCJvQ1F2lOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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