SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8067e8af37ca8ad4bd52506c892675c40ea98221dc60ea92e77d3cf0958f3c97' 
  AND token = 'hwHRIvnKGF9WUqdCh9dzHgAh2rxUpP0RmaeSKzApHNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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