SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b13be4014ba7605e4eb8328566cc03b0594e72a95d5becc4af69775ffca1a918' 
  AND token = 'qTt0rJZBzwEVClYG3krjNd+k99iMX6prWv4lKM0ojB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}