SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c185a9d5cb5cb563a4282dda927cb9a3c0ef5303e710f62e2c2d4b4b22b1a94' 
  AND token = '8cQDlPF+VFmw47s51tXZ8v/CO/odBqoJO9IgLMPy1K0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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