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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81f328e77cbf259b08aa067a18cd25aef09d48f3e8bbf3357b91ee4721463cc8' 
  AND token = 'THolAKaRlT73Vrd9a2UkmyC3NM0c7LHNQhwqVqWEy+M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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