SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da423f83794112c8347a712ada0956bcadb74eb92ee65945bfb10981cd4f8aa3' 
  AND token = 'hfIrAvqyH6jyWjf2nJDll1EghVxYEVXe2zbc9UILsj4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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