SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55aa5baba44c65b7d94e7e058413db34097ebc4beaef5d8edac5dd607d0f6647' 
  AND token = 'MkuevKT69W0LgjpHGR77MdHJLu3/lGtfM3gVinSNKAk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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