SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96ced78ccabcd4d66e24fecd6c18f420a0d4092d1d713cf5a5b93c02a8987a51' 
  AND token = 'fNgP9tCrBKx8ilGceZp6AHbzupACmvizPsjHrhFcZq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}