SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fb4ea97a5a664dfc782c8b91f4d3fe5a8d9a2b2531879147cd241a143b6606e' 
  AND token = '4p4NFvVGit0TISQFGP0JezYiTXkBvJwU/WHfEAFxkOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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