SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf2a15826aba3be9684001b1819564bdb1b3a8fb46a535b8822c93fe0a4a5f0f' 
  AND token = 'zGjCSkxf8dC4sja1vTqhS7VbiwtWWPh/ZgD5NLCQg+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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