SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a0e6ee9e2f573a678607e438706a5759a032da4705918e5f829912405dbabba8' 
  AND token = '8zJG57SOsK6+hq2JgcggbnFSF6638VPbgPbGNiFsud4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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