SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66e796b6134cf2d3c90ebdb1bf416565199193e31204d6f5a2e93524adbb8ebc' 
  AND token = 'Ei78UbAmCyG2V1KcgROP12joQl9yrxEGzwfY5QYr2m0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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