SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59945e894622d487eef4840402402674daa4cb95ae8f4cee4b53079c05a4b4a9' 
  AND token = 'vtqOOOveaxVBJrg4jMNYeIRt5GLvk1RsOhNhZ9GaHiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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