SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16f387dcb9d9037a5ee420609c58c9f2dab59c68d3b341ff02c11176ec8deb88' 
  AND token = 'bJ60qXw9rKBM3hs5SZbKeAsrJFoRCBl+QlEYV2Qxq4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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