SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd11904b9b2b427b7356b299a30644e0d2429dc2136f26048fa6bb72914933b02' 
  AND token = '+KcjuxqOcq96YVn0EmKfsxZiG7Zpoh9+CHicw5cRFLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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