SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb0e4dbfd090ba7d1fdba95ef96af94ba8e6cd0985df5493726c2faeb1e5e9fa' 
  AND token = 'T7CeKlykPeJkM8ULzfOL56LB1B4IYAsjtdPi/14ZCyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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