SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '894d725dfb0dc4491df2a1635c0bb9d375230712d796f659e3a2aa8a314ceadb' 
  AND token = 'BmTnuKQI4/6BfexhiuK7gUqFdP4IyuvBgfa3Y8fULjE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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