SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d4e28aeb08b1fc676bd6754c74362f00b1204a026e6bb29f2772b3e50baf96b' 
  AND token = 'vzCwEfJnxLhuWkbHiMs97bCVnc2L0542UdeZSDSfePs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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