SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a965d3abe36c68f9b3b8525567335849aadd1dd0928adf00f631146a55045a17' 
  AND token = 'DGyiTk7cT4BHAXNXLqapoXp6MOiUkGdM/uEJcFXWUKI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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