SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '108afaabb0974121e083d43b28786eb6479f2fe75dfbca08a2e6d7d34d7e3532' 
  AND token = 'fhJJqEKEUhiNQypNzQY8NE7P7I3sZsIuMBmVQ2OOHiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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