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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03ff33d3ab5ab688a5cc4044db7483ed633292c8a8d5c731a50afe2e43e88347' 
  AND token = 'ufierLwz4xOzqdsFm0S/JKufSdR/jOyMVj0B6rtZmIs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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