SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a7e10295dd56203f6993e33640c6a8cc40503d84de7e24c103dafc281199a01' 
  AND token = 'jDK72sxxR7Jon+gj45kB+DaBZxmloU4GlLsB6xhEFME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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