SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0c096682d03d7b3620679d95319fa78207d8a570b69240fafadfd5a7bc5f450' 
  AND token = '8JJWlV9avXgnbbpIKmn/3gpPBkDU0OjKYseiEyPBFMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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