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SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ffcb31f07a3deefafd2d4802fa7da405d46a50531617be0f558f3e1ae6fabea0' 
  AND token = 'vLiI0sQpy+ghQ6v6U8KTOQZu6h6O6EuoUjZ9XGzxo4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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