SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fbbf9ac4742be75250885a9a45cdaed4387a490e711dd25860bec827c5f771e4' 
  AND token = 'nuJtLNSbQrV9dPnTDsnkGz1K2PCzWAUaPomBVWFYMD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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