SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c810daf4294082610681b41888caa13c07ce13bb772bf7989d8d17e7df505b81' 
  AND token = 'WLEwqaUQWYsmqHvNRqbqQYa20Zw0MW993xK8stlU0sE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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