SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b51746d85d0f8a53e3b9a5ca15e0627a620f1e581bced92d93c6976f6db5c40' 
  AND token = 'PpVliiPWnGa2l3U1C/5trYZpclp5TsCGx8PBg806hCI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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