SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3320860b372ff57d5dfc4f2b219225c9b7b34726a18a2950bd3bc19b966d598' 
  AND token = 'WJlVrs/R4NOhiTIrB6SD9dqoAj/sw5Yez6mMpBZL5os=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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