SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '334b466e98fbe0d6065088bb019468b2aadee4482b202677e87bd234c3034547' 
  AND token = 'vUQQJP3KTMzSn57RKyHnYDjfzHBUPScFv4+Q1FMaX1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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