SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3794f2393a0f84d0ffc427ca28a459945c22dbe5ecaacaacd738421a98dffae' 
  AND token = 'HlMn4jtXphojbLrM+/A5ZRegrmHSfRVUAwXD9Ox5p9M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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