SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a429e23fe64d9107d32f7e18507e194bb5e42527162269d661fe89d0d0f35a0a' 
  AND token = 'ZnPjcg1/Aij/QXKgIp+QAm7GBFKmQfZxT0zyLKAMCsA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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