SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '71a693efc6621d302759e33da90a20a6465897ce1011827f03d1c6f7f4c93db1' 
  AND token = 'njHfjvYN6B3Btz54VhuMpv5iLhx4quIGxq04d3SrAZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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