SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f4be27c111357fe16abc1919ac5d487c0a6511ce4b1fbe7c3293e1a84535c4f' 
  AND token = 'rjAxYJ5xCrzo2Bu1cscQGwzpO7WaBuqsdr5jDG5l0Y4=' 
  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"
    }
  }
}