SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd80a0990063548e7b8d9c4eb25417a8104720b534bcb8dfade9b2bd6203324d' 
  AND token = 'NNB3aCSpSmwGLZXtN3JZ79usuRgDMqabbRI9CmdWRZY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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