SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f14849bef90840d7aac670992dbd45fd743abf6bbe81e7f2f4029a49992cba5' 
  AND token = '4BxbF7sGfrHVMRsRYTifPneF7JE2oCx/BifOI0v6y1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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